////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2011-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if ! defined (octave_interpreter_qobject_h)
#define octave_interpreter_qobject_h 1

#include <QObject>

#include "qt-interpreter-events.h"

namespace octave
{
  class interpreter;

  class base_qobject;

  class interpreter_qobject : public QObject
  {
    Q_OBJECT

  public:

    interpreter_qobject (base_qobject& oct_qobj);

    ~interpreter_qobject (void) = default;

    qt_interpreter_events * qt_link (void);

    void interpreter_event (const fcn_callback& fcn);

    void interpreter_event (const meth_callback& meth);

    void interrupt (void);

    // Note: PAUSE, STOP, and RESUME are currently only used by the new
    // experimental terminal widget.
    void pause (void);
    void stop (void);
    void resume (void);

  signals:

    void ready (void);

    void shutdown_finished (int);

  public slots:

    // Programming Note: With the current design of the interpreter,
    // additional signals will not be noticed because the execute
    // function starts the Octave interpreter and it doesn't return
    // until the interpreter exits.  So the Qt event loop running in the
    // thread where the interpreter_qobject object lives never has a
    // chance to see another signal.  Changing the design of the
    // terminal widget as proposed and discussed here:
    //
    //   https://lists.gnu.org/archive/html/octave-maintainers/2019-05/msg00115.html
    //   https://lists.gnu.org/archive/html/octave-maintainers/2019-06/msg00009.html
    //
    // coulld solve that problem.  Briefly, instead of having the Octave
    // interpreter block and wait for keyboard input, the terminal
    // widget would be in charge of accepting keyboard events and use
    // readline in callback mode.  Then the terminal widget and the
    // interpreter will not block except when executing code.  Then we
    // could have the interpreter qobject directly accept signals.

    //! Initialize and execute the octave interpreter.

    void execute (void);

  private:

    base_qobject& m_octave_qobj;

    interpreter *m_interpreter;
  };
}

#endif
